In general, a reciprocating compressor is for compressing fluid such as air or coolant gas, etc. A compressor includes a motor part installed in a sealed container and generating a driving force and a compression unit for sucking and compressing coolant gas by receiving the driving force of the motor.
The compressor is divided into a rotary compressor, a reciprocating compressor and a scroll compressor, etc. according to a gas compression mechanism of the motor part and compression part.
As depicted in FIG. 1, in the rotary compressor, according to rotation of a rotor 2 of a motor part M installed in a sealed container 1, a rotational shaft 3 inserted into the rotor 2 is rotated. By the rotation of the rotational shaft 3, a rolling piston 5 inserted into an eccentric portion 3a of the rotational shaft 3 and arranged in a compression space P of a cylinder 4 contacts to the inner circumference of the compression space P of the cylinder 4. In that contact state, with a vane (not shown) inserted into a certain side of the cylinder 4 in order to divide a high pressure region and a low pressure region, the rolling piston 5 compresses the coolant gas sucked into a suction hole 4a of the cylinder 4 and discharges the gas through a discharge flow path while being rotated in the compression space P of the cylinder 4, and the operation is performed repeatedly.
As depicted in FIG. 2, in the reciprocating compressor, a crank shaft 13 inserted into a rotor 12 is rotated according to rotation of the rotor 12 of a motor part M installed in a sealed container 11. By the rotation of the crank shaft 13, a piston 14 combined with an eccentric portion 13a of the crank shaft 13 compresses coolant gas sucked through a valve assembly 16 combined with the cylinder 15 and discharges the gas through the valve assembly 16 while performing a linear reciprocating motion inside a compression space P of a cylinder 15, and the operation is performed repeatedly.
And, as depicted in FIG. 3, in the scroll compressor, a rotational shaft 23 having an eccentric portion 23a inserted into a rotor 22 is rotated according to rotation of the rotor 22 of a motor part M installed in a sealed container 21. According to the rotation of the rotational shaft 23, because a slewing scroll 24 connected to the eccentric portion 23a of the rotational shaft 23 performs a slewing motion while being engaged with a fixed scroll 25, volume of plural compression pockets formed by involute-curved wraps 24a, 25a respectively formed at the slewing scroll 24 and the fixed scroll 25 is decreased, and accordingly coolant gas is sucked, is compressed and is discharged in the operation. The operation is performed repeatedly.
Hereinafter, the rotary compressor, the reciprocating compressor and the scroll compressor operated by different compression mechanisms will be described in the structure and reliability aspects.
First, in the structure aspect of the rotary compressor, the rotary compressor includes the rotational shaft 3 having the eccentric portion 3a, the rolling piston 5 inserted into the eccentric portion 3a and plural balance weights combined with the rotor 2 so as to maintain the rotation balance of the eccentric portion 3a. Because the rotary compressor has lots of construction parts, a structure thereof is a little complicate.
In addition, in the reliability aspect of the rotary compressor, because the eccentric portion 3a formed at the rotational shaft 3 and the rolling piston 5 are rotated eccentrically, lots of vibration noise occurs in rotation.
And, in the structure aspect of the reciprocating compressor, the reciprocating compressor includes the crank shaft 13 having the eccentric portion 13a, the piston 14 combined with the crank shaft 13 and a balance weight 13b for maintaining the rotation balance of the eccentric portion 13a. Because the reciprocating compressor has lots of construction parts, a structure thereof is a little complicate.
In addition, in the reliability aspect of the reciprocating compressor, because the eccentric portion 13a formed at the crank shaft 13 is rotated eccentrically, vibration noise occurs, in addition, the valve assembly 16 is operated in suction and discharge, lots of suction/discharge noise occurs.
And, in the structure aspect of the scroll compressor, the scroll compressor includes the rotational shaft 23 having the eccentric portion 23a, the slewing scroll 24 and the fixed scroll 25 having the involute-curved wraps and a balance weight for maintaining the rotation balance of the eccentric portion 23a. Because it has lots of construction parts, a structure thereof is very complicate. In addition, it is very difficult to fabricate the slewing scroll 24 and the fixed scroll 25.
In addition, in the reliability aspect of the rotary scroll, vibration noise occurs in the slewing motion of the slewing scroll 24 and the eccentric motion of the eccentric portion 23a formed at the rotational shaft 23.
As described above, in the rotary compressor, the reciprocating compressor and the scroll compressor, the compression part compresses gas by receiving the rotational force of the motor part, when a compressor is installed in a cooling cycle, the number of rotations of the motor part has to be reduced or the rotation of the motor part has to be stopped in order to adjust a quantity of compression gas, and accordingly it is difficult to adjust a quantity of the compression gas accurately.
In addition, by respectively forming the eccentric portion 3a, 13a, 23a at the rotational shaft rotated by receiving the rotational force of the motor part, the balance weight 6, 13b, 26 are required, lots of driving force is consumed, vibration noise occurs in the operation, and accordingly reliability of the compressor is lowered. In addition, because of complicated structure, assembly productivity is lowered.